STIEBEL ELTRON SOL 25 PLUS - Manual (Page 68)

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develop which would cause the system to stop working properly.
controller: an electronic device that senses temperatures and uses
control algorithms (rules) to determine when to activate pumps and
relays and various warnings and alarms. The controller serves as
the “brain” of a solar thermal system and controls how and when
the system collects heat, sheds excessive heat, and shuts down to
protect various components.
DHW: domestic hot water
DHW mixing valve: a temperature-sensitive regulating valve that
mixes cold water with incoming hot water to limit its temperature to
prevent scalding and other problems for end users.
Dowfrost™ 50: ready-mixed propylene glycol heat transfer medium
that contains approximately 50% propylene glycol anti-freeze fluid.
EPDM: ethylene propylene diene monomer (M-class) rubber, a
synthetic rubber that exhibits outstanding heat, ozone and weather
resistance and is often used for sealing components in heating
systems.
expansion tank: a tank that is attached to heating systems to allow
normal expansion of liquids that undergo heating and cooling
cycles in order to prevent undue stress on (and failure of) piping,
tanks, fittings, and other vessels. Most modern expansion tanks
have a chamber filled with air or nitrogen that provides a cushion
against which the system liquid may expand; this chamber is
typically isolated fluidically by a rubber membrane (diaphragm)
that is chemically compatible with the system liquid and capable of
withstanding the temperatures of that liquid.
flowmeter: a device used to measure or display fluid flow rates in a
fluidic system. They may be electronic or mechanical. Mechanical
flowmeters often use an annular orifice/venturi/float system for
measuring flow rates.
Flowstar: brand of pump station used in Stiebel Eltron SOLKIT solar
systems. The contain a circulator (pump), expansion tank, pressure
relief valve, 2 boiler drains, temperature/pressure gauge, flowmeter,
check valve, return line thermometer, and air vent.
frame connector (splice): a set of hardware that allows the collector
profile (frame) rails to be connected, end-to-end, to form a row
array of solar collectors.
GPH: gallons per hour
GPM: gallons per minute
GRAS: Generally recognized as safe (GRAS) is an American Food and
Drug Administration (FDA) designation that a chemical or substance
added to food is considered safe by experts, and so is exempted
from the usual Federal Food, Drug, and Cosmetic Act (FFDCA) food
additive tolerance requirements. For solar thermal systems, the
GRAS (non-toxic, food grade) designation is often required of the
propylene glycol heat transfer medium if there is a possibility of the
medium’s being introduced into the potable water.
hard-solder: 95/5 lead-free solder used to join piping in the solar
loop. It is capable of withstanding the elevated temperatures that
solar collectors are capable of generating.
heat-conducting paste: a thermally-conductive paste that aids in
transferring heat between components. This paste is typically used
in solar thermal systems to allow temperature sensors to read
temperatures of components more accurately.
heat exchanger: a device used to efficiently transfer heat between
one component and another. In heating systems, heat exchangers
are most often used to transfer heat between two separate fluids.
There are liquid-to-liquid, liquid-to-gas, and other types of HX.
heat transfer medium: fluid that is used to collect and transport heat
energy between solar collectors and storage tanks or other devices
in a solar loop.
horizontal collector mounting: a mounting arrangement in which
the short dimension of each collector is oriented up/down; the
collector’s pipe fittings (nipples) point horizontally (to the sides).
Hx: heat exchanger
hydrometer: an instrument used to measure the specific gravity (or
relative density) of liquids; that is, the ratio of the density of the
liquid to the density of water. In solar thermal systems, it is often
used to test the composition of the heat transfer medium.
insolation: incoming solar radiation that impinges upon a solar
collector or other surface.
installed height: the height above surrounding grade, usually in
reference to the height of the solar collectors.
isolation valve: a valve used to cut off and isolate a device (e.g., a
vent valve or an expansion tank) from the rest of a fluidic system.
lightning protection: equipment and measures used to ensure that
particular equipment and attached structures are protected from
lightning strikes and induced charges; these often include special
grounding cables and clamps to safely conduct current to earth
ground.
MSDS: material safety data sheet – a data sheet that usually
accompanies many chemicals and other materials to allow users to
take appropriate measures to ensure their safe use.
mounting frame: an assembly of hardware that forms a frame in
which solar collectors are held in place on a roof or other structure.
pipe run: the piping in a solar loop (circuit) that connects the
collector(s), pump station, and heat exchanger(s) in storage tank(s).
polyisocyanurate: foam typically used as rigid thermal insulation.
Its thermal conductivity has a typical value of 0.16 BTU*in/hr*ft2*°F
(0.023 W/mK). It has superior resistance to breakdown at high
temperatures, which is necessary for solar loops.
pre-charge pressure (of expansion tank): the pressure of the gas